Servers provide data and services to client devices. For example, a data center comprising a plurality of servers may service clients over a network. For various reasons, servers and data centers may be subject to performance degradations. A conventional server monitor typically monitors traffic going through the server and reports on a current operational state of the server such as whether server applications are up and/or response times of the server applications. Conventional monitors typically do not analyze the traffic and service characteristics to provide information about health of a group of servers or provide warnings about the server. Thus, there is a need for a server monitoring system that provides a holistic report of server health and provides warnings about changes to server health.